Switching means



Oct. 22, 1935. T G, LE CLAIR Er AL 2,017,907

SWITCHING MEANS 2 Sheets-Sheet l4 Filed Aug. 20, 19.31

17a/mmm Oct. 22,-1935. T. G. LE CLAIR Er A1. 2,017,907

SWITCHING MEANS Filed Aug. 20, 1951 2 Sheets-Sheet 2 Patented Oct. 22, 1935 UNITED STATES PATENT GFFICE SWITCHIN G MEANS Application August 20, 1931, Serial No. 558,227

7 Claims.

The present application is a continuation in part of our copending application Serial No. 464,554, led June 28, 1930 now matured into Patent No. 1,916,844, granted to us July 4, 1933.

This invention relates to electric contact clips, especially such as are particularly adapted for use on switches of high current carrying capacity, and it is one of the objects of the present invention to provide a contact clip of the full oating type which can receive a switch blade from either direction and which will nevertheless exert a firm pressure upon the switch blade throughout its entire contact making area.

The contact of the present invention is particularly adapted for use on' drum type switches. In the switch of the present invention the movable contact making member comprises a switch blade which is movable into and out of its full closed position between the Contact shoes by a motion which is at times clockwise and at other times counterclockwise. The contact construction must be such as `to produce a uniform contact pressure and an alignment of the contact shoes regardless of the direction from which the blade approaches the contact. The contact is maintained in pressure engagement with the blade through the action of spring means. To maintain a uniform pressure on the blade regardless of the direction of approach of the blade we provide two springs for each contact Shoe. The springs are located at the rear of the shoes, as is usual, and are placed one adjacent each edge of the shoes. By this arrangement a full floating action is maintained.

It is a further object of the present invention to provide an improved contact clip holder adapted to hold a clip of the above type. The clip holder comprises a channel shaped member adapted to hold the contact shoes between its flanges. On the inner side of the anges we provide means forl holding the contact shoe pressure springs. This means may take the form of a pair of strips of metal secured to the flanges in spaced relationship and extending at right angles to the web of the channel. The springs used are leaf springs with the ends of each spring guided in the space between a pair of such strips. This provides a simple and rugged construction into which the springs with the contact shoes attached thereto may be easily inserted or removed.

The attainment of the above and further objects of the presentrinvention will be apparent from the following specification taken in conjunction with the accompanying drawings forming a part thereof.

In the drawings:

Figure l is a. fragmentary view of a portion of a switch employing our improved contact, said 5 View illustrating an end View of our contact with a switch blade in its open position;

Figure 2 is a sectional View taken .along the line 2 2 and looking in the direction of the arrow; l0l

Figure 3 is an enlarged top View of our improved contact;

Figure 4 is an end view thereof;

Figure 5 is a top view of a modified form of switch contact constructed in accordance with 15 the teachings of our invention;

Figure 6 is .a side view thereof;

Figure 7 is an end View thereof; and

Figure 8 is a perspective view of the frame of the Contact shown in Figures' to 7. 20

We have herein iliustrated our improved contact as incorporated in a switch of the type shown in United States Patent No. 1,916,844, issued to us July 4, 1933, and to which reference may be had for aY further description of the 25 switch itself. Since the switch itself does not constitute the subject matter of the present invention and since the contact may be incorporated in switches of speciiically different constructions we have herein illustrated only a frag- 30 mentary portion of the switch itself.

'I'he switch is mounted in a tank I which may be of any preferred construction and which contains a bath of insulating oil for the switch. A switch base 2 of slate or other insulating ma- 35 terial is suitably mounted in the tank l and supportsY the switch. The switch blade is indicated at 3 and comprises a plate-like member having contacting surfaces at 4 and 5. The switch blade is mounted upon a shaft 6, of wood 40 cr other suitable insulating material, and is adapted to be actuated upon rotation of the shaft. The shaft 6 may support many such switch blades in spaced relation and having contacting portions in different angular relationship 45 to the contacting portions 4 and 5. The shaft 6 is supported at its opposite end in suitable bearings supported upon brackets in any preferred manner.

Thefswitch contact which is adapted to receive 50 f which holds the contact shoes. The base of the clip is indicated at I2 and the flanges thereof at I 3|3. The clip is preferably, although not necessarily, made of copper or other suitable material of high electrical conductivity. The base or web I2 of the contact holder is provided with two tapped holes indicated at I4 and I5 for receiving bolts I6 (Figure 2) for rigidly mounting the contact holder upon the slate base 2 and for establishing an electric circuit between a bus I1 and the contact clip. The bolts I6 are preferably made of copper or other suitable metal of high electrical conductivity and thereby constltute the means-for extending the circuit from the bus bar I1 to the clip holder. A pair of contact shoes 20 and 2| are disposed between the flanges |3|3 of the clip holder or frame II. Each of the contact shoes ismade of copper tub-y ing through which a iiexible braided conductor 24 is extended, the tubing being thereafter flattened upon itself in a suitable press to compress the tubing upon the flexible conductor and to give the tubing a flat contacting surface on one side. The tubing may have its ends cut off obliquely to produce a taper such as shown in Figure 4. A pair of flat leaf springs 26 and 21 are bent in a generally LJ-shape and are secured to the opposite ends of the contact shoes 2l) and 2| by means of rivets or the like as indicated at 28. Each of the rivets 28 passes through` a hole in the respective contact shoes from the rear thereof, and serves to secure the web portion of the U-shaped spring to the contact. The ends of each of the rivets 2B adjacent the front faces 25 of the contacts are preferably made flat so as not to interfere with the sliding movement oi the blade between the contact shoes during the opening or-closing of the switch. To facilitate this the rivet holes in the vfront face 25 of the contact shoes are preferably countersunk. The opposite ends of the springs 26 and 21 are free and are guided between two strips of metal 3D and 3| that are secured to the flanges of the frame ID by means of suitable rivets or screws 32. The inner strips 3| may be: omitted if desired since the outer strips 30 effectively hold the springs against side movement. The ends of the braided conductors 24 have suitable terminals secured thereto. These terminals may comprise merely short lengths of tubing of copper or the like into which the ends of the flexible braided conductors are passed and which are thereafter compressed upon the ends of the conductors by pressing the same in a suitable punch press. The terminals 36 are removably secured to the contact frame by means of suitable bolts 36-36 that extend through suitable openings formed in the terminals 35 and are threaded into suitable openings in the flanges |3-I3. The bolts are preferably, although not necessarily, formed of copper or other suitable metal of high electrical conductivity. The ends of the contact shoes 20 and 2| are curved away from one another as indicated at 38-38 in order to facilitate the movement of a switch blade between the two contact shoes. It is to be noted that the contact shoes are outwardly flared at both ends. This means that the blade will be guided between the contactl shoes when it approaches the same from either direction, that is, when the shaft 6 (Figure 2) is turned in either a clockwise direction or a counterclockwise direction.

The springs 26 and 21 constantly urge the two contact shoes towards one anotherso that their contacting faces are in engagement when the switch is open. As the switch blade is moved between the contact shoes it forces them apart. The springs 26 and 21 maintain the contact shoes against the opposite sides of the switch blade and insure the maintenance of a suitable contact pressure between the contact shoes and the blade. It is to be noted that the contact shoes are full floating and may readily adjust themselves to any angular position as determined by a slight angular irregularity in the position.

of the blade, should this be necessary.

The metal strips 3B and 3| denne grooves withinwhich the ends of the springs 26 and 21 are held against side motion but are permitted a free up and down motion with reference to the base of the channel member II. As a result of this construction it is possible to readily remove the contact shoes from 'the holder by merely pulling upward on the same. This may be neces- Sary in order to clean the contact shoes or to le down any pitting or burning that may have taken place. The contact shoes may then be readily inserted in the clip holder by merely sliding the ends of the springs into the channels defined by the strips 30 and 3|. It is also to be noted that the space between the strips 30 and 3l is slightly greater than the width of the springs 26 and 21. This allows the contact shoes a limited amount of free play lengthwise of the channel contact frame.

In Figures 5 to '7, we have indicated a modified form of switch contact constructed in accordance with the teachings of our invention. The contact frame, which is shown in perspective in Figure 8, is indicated in general by the reference numeral 50 and comprises a channel-shaped frame of copper or the likehavinga web 5| and a pair of flanges 52 and 53. The web is provided with holes 54-54 for mounting the same, said holes corresponding to the holes Ill-I5 of the contact previously described. The flanges 52-53 of the channel are tapered, being widest adjacent the web 5| and narrowest at 45 their outer ends.

The contact shoes are indicated at Sil-60 and are formed of copper tubing compressed upon a flexible conductor 6| extended therethrough,

as in the case of contact shoes of the contact previously described. Terminals 62 are formed at the two ends of each of the flexible conductors 6| of the respective contact shoes and are secured to the flanges 52-53 of the channel-shaped frame member by means of suitable bolts or the like. The ends of the contact shoes are bent back as indicated at 65 and 66 to form flanges embracing the tapered sides of the flanges of the channel-shaped contact frame. The flanges 65 and 66 are bent at an angle corresponding to the taper of the flanges 52 and 53 of the contact frame. The lower end corners of the bent back flanges 65-66 are cut away as indicated at 6l, to cause the bottom of the flanges 65-66 to lie in the same plane as the web 5| of the channelshaped frame.

The contact shoes are adapted to receive a switch blade between them and are urged toward one another by means of a pair of leaf springs indicated at 66-68. The leaf springs may be secured to the respective contact shoes in the same manner as is illustrated in Figure 4, or they may be entirely separate from the contact shoes. The ends of the springs bear against the Vflanges 52-53 whereas the intermediate portion bears against the contact shoes. In the present form of contact one spring is used for each contact shoe whereas in the previously described construction two sets of springs were used for each contact shoe.

As previously pointed out, the anges 65-65 of the contact shoes embrace the flanges 52-53 of the contact frame 50. This arrangement avoids the necessity of strips such as strips Ell-3l of Figure 3 for limiting the side movement of the contact shoes in the Contact frame. It is to be noted that there is a slight clearance between the flanges 65-66 and the tapered surfaces on the flanges 52--53 of the contact frame. This permits a limited amount of free play of the contact shoes in the contact frame in a direction lengthwise of the channel of the frame.

In compliance with the requirements of the patent statutes we have herein shown and described a preferred embodiment of our invention. It is however to be understood that our invention is not limited to the precise construction herein disclosed, the same being merely illustrative of the general principles of the invention. What we consider new and desire to secure by Letters Patent is:-

1. A switch contact having a channel shaped contact holder, a pair of contact shoes between the anges of the channel and movable at right angles to the planes of the flanges, and U-shaped leaf springs disposed between the' flanges and the contact shoes and urging the contact shoes towards one another, said springs being secured at their bight portion to the contact shoes and bearing with their free ends against the flanges of the holder, and said holder having a groove formed therein for guiding the free ends of the springs.

2. A switch contact comprising a channel shaped contact holder, a pair of contact shoes disposed between the flanges of the channel and movable towards one another in a direction at right angles to the plane of the flanges, said contact shoes being outwardly flared at both ends thereof for guiding a switch blade between them from either end, and spaced U-shaped leaf springs adjacent each of the outwardly flared portions for urging the contact shoes towards one another, said springs bearing at their bight portions on the contact shoes and at their free ends against the flanges of the contact holder.

3. A switch contact holder comprising a channel shaped member having on the inside of each flange contact spring guiding means comprising a pair of spaced strips secured to the flange and defining a spring guiding groove.

4. A switch Contact comprising a channel shaped frame the flanges of which are tapered, rocking contact shoes disposed between the flanges and loosely embracing the tapered portion thereof, and spring means bearing against the flanges of the channel and the contact shoes for urging the contact shoes towards one another.

5. An electric switch including a contact making member and a contact structure engageable thereby as it moves in a plane into its switch closed position, said contact structure including a channel-shaped frame rigidly mounted with the flanges thereof lying on opposite sides of the plane of movement of the contact making member, contact shoes loosely disposed between the flanges and adapted to receive the contact making member, spring means urging the contact shoes away from the flanges into firm engagement with the opposite sides of the contact making member, the contacting faces of the shoes being approximately in the plane of movement of the contact making member and free to tilt a substantial amount angularly with respect to the planes of the flanges under the action of the contact making member to bring the entire contacting surface of the contact shoes exactly into the plane of movement of the contacting por- 15 tions of the contact making member and into full engagement with the opposite sides of the contact making member, said contact shoes having lianges loosely embracing the flanges of the channel to limit the movement of the contact 20 shoes longitudinally of the channel while permitting a complete freedom of angular movement to effect alignment of the plane of the contacting surfaces of the contact shoes with the plane of movement of the contact making member, the 25 flanges of the channel being tapered to permit an increase in the extent of tilting of the contact shoes by movement thereof outwardly of the web of the channel.

6. In combination, a contact making member 30 movable into and out of switch closing position, a contact structure adapted to be engaged by said member in switch closed position, said structure comprising a channel-shaped frame member having its extending flanged portions tapered toward 35 the extending ends thereof, contact shoes loosely disposed in the channel of said frame member, spring means biased between said shoes and said flanges for urging said shoes toward each other into firm engagement with the opposite sides of 40 said contact making member, and flexible conductor means connecting said shoes tosaid frame, said tapered flanges providing for an increase in the extent of tilting of said shoes with respect to said flanges as said shoes are moved outwardly 45 from the web of said frame member.

7. A switch contact having a channel-shaped contact holder, a pair of contact shoes having integrally formed spaced vertically extending walls disposed for .floating movement between the 50 flanges of said holder, the adjacent ends of said shoes being flared outwardly away from each other to receive therebetween a switch blade, U- shaped vertically extending leaf spring members having their bight portions engaging one wall 55 of each of said shoes for urging said shoes toward each other to bring the adjacent walls of said shoes into contact, the free ends oi said springs having abutting engagement with the inner surface of said flanges adjacent the top and bottom thereof, flexible mechanical and electrical connecting means secured within the walls of said shoes and extending outwardly of the ends oi' said shoes, and means for securing said connecting means to the outer surfaces of said flanges.

TITUS G. LE CLAIR., CHARLES M. GROSS. 

